Evaluate the esthetic perception and attractiveness of the smile with regard to
the buccal corridor in different facial types by brachyfacial, mesofacial and
dolichofacial individuals.

Material and Methods:

The image of a smiling individual with a mesofacial type of face was changed to
create three different facial types with five different buccal corridors (2%, 10%,
15%, 22% and 28%). To achieve this effect, a photo editing software was used
(Adobe Photoshop, Adobe Systems Inc, San Francisco, CA, EUA). The images were
submitted to evaluators with brachyfacial, mesofacial and dolichofacial types of
faces, who evaluated the degree of esthetic perception and attractiveness by means
of a visual analog scale measuring 70 mm. The differences between evaluators were
verified by the Mann-Whitney test. All statistics were performed with a confidence
level of 95%.

Results:

Brachyfacial individuals perceived mesofacial and dolichofacial types of faces
with buccal corridor of 2% as more attractive. Mesofacial individuals perceived
mesofacial and dolichofacial types of faces with buccal corridor of 2%, 10% and
15% as more attractive. Dolichofacial individuals perceived the mesofacial type of
face with buccal corridor of 2% as more attractive. Evaluators of the female sex
generally attributed higher scores than the male evaluators.

Conclusion:

To achieve an enhanced esthetic smile it is necessary to observe the patient’s
facial type. The preference for narrow buccal corridors is an esthetic
characteristic preferred by men and women, and wide buccal corridors are less
attractive.

Key words: Orthodontic treatment; Esthetics; Orthodontics

INTRODUCTION

A balanced and attractive smile is a primordial treatment objective of modern
orthodontic therapy4,12,13,15,16,18. Dentofacial appearance is one of the main determinants of physical
attractiveness1,8. During interpersonal interaction, individuals'
focus is mainly centered on the other person’s eyes and mouth, with little time spent on
the other facial characteristics5. In the opinion
of the public, the smile appears in second place, losing out only to the eyes as the
most important feature in facial attractiveness8.

Understanding the attractiveness of the smile and the buccal corridor space is
important, since it provides a hierarchy of esthetic preference10,11. In the
smile, bilateral spaces appear between the vestibular surface of the maxillary posterior
teeth and the internal mucosa of the cheek, denominated buccal corridor17. Few studies have related the buccal corridor and
its influences to different facial patterns. Based on this premise, the aim of the
present study was to evaluate the perception of the esthetics and attractiveness of the
smile with regard to the buccal corridor in individuals with brachyfacial, mesofacial
and dolichofacial types of faces, by three groups of academic personnel, previously
identifed according to facial type (brachyfacial, mesofacial and dolichofacial).

MATERIAL AND METHODS

An individual with a mesofacial profle was selected based on a subjective analysis of
the problem (Figure 1). The individual received
previous orthodontic treatment, in which he presented complete dentition and no rotation
in the anterior region. The individual signed an informed consent form stating that he
authorized the modifcation of the images to be used in the present study.

Figure 1 Initial frontal picture without any alteration. The patient signed informed
consent authorizing the publication of these pictures.

A front view photograph was taken with a digital camera (Canon Rebel XTI, Tokyo, Japan),
with a standardized beam-focus distance. After the image was obtained, a photo editing
software (Adobe Photoshop, Adobe Systems Inc, San Francisco, CA, EUA) was used for
removal of small imperfections and asymmetries that could influence the evaluation of
attractiveness. From the modifcation of this image, two other facial images were
obtained (brachyfacial and dolichofacial). Five images were produced for each profle,
creating a series of five different smiles: narrow (buccal corridor 2%), medium-narrow
(buccal corridor 10%), medium (buccal corridor 15%), medium-wide (buccal corridor 22%),
and wide (buccal corridor 28%).

The images were shown by means of the PowerPoint presentation software (Microsoft Offce
2007, Redmond, WA, EUA). In the first stage of evaluation 15 images (5 images X 3 facial
types) were randomly organized and numbered from 1 to 15; the presentation time was 10
seconds for each photo (Figure 2). In the second
stage of evaluation the images with the same buccal corridor measurement and with the
three different facial types (A-brachyfacial; B-mesofacial; C-dolichofacial) were
grouped in a single slide, totaling 5 slides. The slides were numbered from 1 to 5 and
organized in the following buccal corridor sequence: 15%, 28%, 2%, 10% and 22% (Figure 3). In this category the evaluators had to
respond whether they were able to note the difference between the images; which was the
image they liked most, and which they liked least; and then give scores to each image.
The presentation time for each image was 45 seconds. The evaluators could not return to
previous images in any of the categories.

Figure 2 Set of five different smiles in three different facial types. A=brachyfacial;
B=mesofacial; C=dolichofacial. The numbers 1, 2, 3, 4, 5 and 6 represent the
buccal corridor sizes of corridor buccal 0%, 2%, 10%, 15%, 22% e 28%, respectively
(from the left to the right). The patient signed informed consent authorizing the
publication of these pictures.

Figure 3 Set of different facial types with the same size buccal corridor presented in
a single image, (A) brachyfacial, (B) mesofacial and (C) dolichofacial. In this
case the buccal corridor is 0%. The patient signed informed consent authorizing
the publication of these pictures

A 70 mm long visual analog scale (VAS) was used to evaluate attractiveness. Numbered
blocks were connected to the scale printed on white paper. The term “not very
attractive” was printed on the left side of the scale and “attractive” on the right.

The image evaluations were performed by three groups of dental students (brachyfacial,
mesofacial and dolichofacial type of face), who were previously identifed according to
facial type. Group (A) was made up of 50 evaluators with a brachyfacial type of face,
Group (B) 50 evaluators with a mesofacial type of face and Group (C) 50 evaluators with
a dolichofacial type of face. The evaluators had a mean age of 21.5 years. Before the
study began, the sample size was calculated, showing the need to perform the study with
a sample ranging from 42 to 65 evaluators. In view of this, it was decided to conduct
the study with 50 individuals per group, which would be a median number
in that interval. All the evaluators were instructed to judge the attractiveness of the
smiles by scores on the VAS.

The data were recorded in a table (Microsoft Offce 2007, Redmond, Wash, EUA) and
submitted to statistical analysis by the Exact Fisher, Mann-Whitney and Kruskal-Wallis
tests, Analysis of Variance and the Chi-square test. The level of signifcance was
established at 5%.

Statistical procedure

The scores given to each image were compared by means of the Kruskal-Wallis test and
a comparison between pairs was performed using the Mann-Whitney test. The frequencies
of the responses given by the evaluators were compared by means of the Chi-square
test. In cases in which the expected frequency was less than five (n=5), Fisher's
exact test was used. The level of signifcance adopted was 5% (α=0.05). The data were
analyzed in the statistical program BioEstat (version 5.0, Belém, Pará, Brazil).

RESULTS

Of the 150 participants in the study, 56 (37.3%) were male and 94 (62.7%), female. The
evaluators with different facial types differed in their judgment about the mesofacial
and dolichofacial types of face with buccal corridor of 2%, brachyfacial with buccal
corridor of 10% and brachyfacial with buccal corridor of 22% (Table 1). For the other types of face and buccal corridors there was
no signifcant difference.

Table 1 Mean and standard deviation ofthe scores given by the evaluators with
differentfacial profiles

a,b Values with different superscript letters are significantly
different (Mann-Whitney test)

In the analysis of the evaluators with the brachyfacial type of face, there was a
difference between the sexes only with respect to the brachyfacial type of face with a
buccal corridor of 2% (Table 2). In the analysis
of the evaluators with a mesofacial type of face, there was difference between the sexes
with respect to the brachyfacial type of face with buccal corridors of 10% and 22%,
mesofacial type with buccal corridor of 2% and dolichofacial type with buccal corridors
of 2%, 15% and 22% (Table 1). The men and women
with a dolichofacial pattern evaluated the buccal corridors of the three types of face
analogously.

Table 2 Mean of scores given by evaluators to the facial type of the image according
to the buccal corridor size, evaluator's facial type and sex

Figure 4 shows a graphic illustration of the means
of scores given by evaluators with different facial patterns on the visual analog scale.
The individuals with a brachyfacial type of face demonstrated that they found the
mesofacial and dolichofacial types with a buccal corridor of 2% more attractive, and
evaluated the buccal corridor of 10% as the most attractive for their own facial pattern
(Figure 2A). The individuals with the
mesofacial pattern demonstrated that they perceived mesofacial and dolichofacial types
of faces with buccal corridor of 2%, 10% and 15% to be more attractive. The individuals
with a dolichofacial pattern demonstrated that they found the mesofacial type of face
with a buccal corridor of 2% more attractive, and evaluated the buccal corridor of 2%
and 10% as the most attractive for their own facial pattern (Figure 2C).

Figure 4 Means of scores on the visual analog scale, given by volunteers with the
brachyfacial (A), mesofacial (B) and dolichofacial (C) patterns, according to the
buccal corridor size and type of face

Table 3 presents the perception of the
evaluators with respect to the differences and preferences for the sets of images
presented. The data of all the images showed that the large majority of the participants
were able to notice the difference between the photos presented, and there was no
signifcant difference among the evaluators with different facial types. Only for image 3
(buccal corridor of 2%), as regards the least preferred photo, there was statistical
difference between the groups of evaluators, with the larger proportion of evaluators
with a brachyfacial pattern liking photo A (brachyfacial) the least, while the
evaluators with mesofacial and dolichofacial patterns liked photos B (mesofacial) and C
(dolichofacial) the least.

Table 3 Perception of the participants regarding differences and their preferences in
relation to the images presented

*Answered only by individuals who perceived differences between the images

‡Exact Fisher Test;

†Chi-square

DISCUSSION

The aim of the present study was to analyze the influence of the buccal corridor on the
degree of attractiveness of the smile of individuals with different facial types. A
large portion of the authors who have investigated the subjects did not divide the
evaluators according to their facial pattern3,5-7,9,11. Other related studies
analyzed the influence of different sizes of buccal corridor only in short and long
faces20. Habitually only the image of the
mouth is used as an evaluation parameter2,10,11,17. Some authors have used front view photos of the entire face for this type
of study9,19. For Sachdeva19 (2012),
the buccal corridor space has minimal influence on the esthetic evaluation of the smile,
with other factors being more important, such as the arrangement of the teeth, tooth
color, gingival architecture, gingival exposure, and lip thickness.

In the literature, some studies have not considered the entire face, which may interfere
in the results, since they do not evaluate the facial pattern and other elements of the
face11,17. A limitation of this study is the use of a single image of an
individual of the female sex, as it has been demonstrated that the sex of the individual
in the photo affects the perception of the attractiveness of the smile3; however, the unisex characteristics of the chosen
individual were important for minimal interference in the evaluation. The changes were
made with the use of photo editing software, which was shown to be a most useful image
manipulation method11,14,18,20. To exhibit the
images, a slide presentation software was used, because of the possibility of obtaining
a larger number of evaluators in a shorter time interval. The exhibition time of each
slide was compatible with the time used in other studies20. The use of a black background between the slides served to detach the
evaluator from the previously evaluated image and not influence the evaluation of the
next image. The evaluators were not allowed to go back to images already evaluated so
that there would be no comparison between them. The five different buccal corridor sizes
served to determine the degree of interference of this factor in the esthetics of the
smile9,20.

The esthetic value of each image was judged by means of a visual analog scale (VAS).
This classifcation scale was designed for minimal restrictions and more freedom to
express a style of personal response in a linear manner10,11. The choice of the 70
mm VAS scale was because it is easy to understand and to evaluate each image in a
subjective manner, from the least to the most attractive.

This was the first study in which the evaluators and the images were divided into
brachyfacial, mesofacial and dolichofacial patterns to verify whether the evaluator’s
facial pattern would have an influence on his/her choice. In contrast to the study of
Zange, et al.20 (2011), men were more critical
than women, and attributed lower scores, except for the evaluators with dolichofacial
patterns, who attributed analogous scores. In a study conducted by Abu Alhaija, et
al.1 (2011), no signifcant differences were
detected between men and women. In spite of the methodological differences, the buccal
corridors of 2% and 10% were considered the most esthetically pleasant type in the three
facial types among all the groups of evaluators, similar to the results described by
Moore, et al.9 (2005). It was found that a wide
buccal corridor was considered less attractive than a narrow one1,18, considering
that irrespective of the evaluator’s facial type, the highest scores were attributed to
the sizes of 2% and 10%, followed by 15 and 22% while the buccal corridor of 28%
obtained the lowest scores.

In the individual evaluation of the images, the brachyfacial evaluators assessed the
buccal corridor of 10% as the most esthetically pleasant for their own facial type;
however, they showed that they perceived the buccal corridor of 2% as more attractive in
the mesofacial and dolichofacial types of faces, revealing greater preference for these
types of faces. The evaluators with a mesofacial pattern revealed that they found buccal
corridors of 2%, 10% and 15% attractive both for their own facial type and for the
dolichofacial type, thus showing that they did not fnd the brachyfacial types with the
different sizes of buccal core very attractive. The evaluators with a dolichofacial
pattern preferred the buccal corridors of 2% and 10% for their own facial type; however,
they revealed that they found the mesofacial pattern with a buccal corridor of 2% to be
the most attractive.

When analyzing the set of images, the majority of the evaluators in the three groups
noted differences with respect to the three types of faces. In this category there was
no signifcant difference between the evaluators with different facial types, except for
the slide containing buccal corridors of 2%, for the larger proportion of those with a
brachyfacial type of face liked the brachyfacial image the least, thus revealing that
they found their own facial pattern with this size of buccal corridor less
attractive.

Further studies should be conducted on the subject, with a view to evaluating, by means
of other methods and parameters, the real influence of the buccal corridor on the
esthetics of the smile, particularly in different facial types.

CONCLUSION

By conducting this study, it could be concluded that:

The individuals with a brachyfacial type of face demonstrated that they found the
mesofacial and dolichofacial types with a buccal corridor of 2% more attractive, and
evaluated the buccal corridor of 10% as the most attractive for their own facial
pattern.

Individuals with a mesofacial type of face demonstrated that they perceived mesofacial
and dolichofacial types of faces with buccal corridors of 2%, 10 % and 15% to be more
attractive.

Individuals with a dolichofacial pattern demonstrated that they found the mesofacial
type of face with a buccal corridor of 2% more attractive, and evaluated the buccal
corridor of 2% and 10% as the most attractive for their own facial pattern.

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